Lightguide plate and lighting unit

Abstract

The invention relates to a light guide plate for a front-light type lighting unit in liquid crystal display systems, which comprises an alicylic structure-containing polymer resin, and has on at least one of major planar surfaces a fine projection-and-depression shape having a reflection function. The object of the invention is to provide a light guide plate for a front-light type lighting unit, wherein the initial adhesion and post-durability testing (at high temperature, low temperature, high humidity, etc.) adhesion of an antireflection layer formed on the light guide plate are improved and the transferability of the fine projection-and-depression shape and light ray transmittance are improved as well, and a front-light type lighting unit using the same.

1 . A light guide plate for a front-light type lighting unit in liquid crystal display systems, which comprises an alicylic structure-containing polymer resin, and has on at least one of major planar surfaces a fine projection-and-depression shape having a reflection function.  
     
     
         2 . The light guide plate according to  claim 1 , wherein the fine projection-and-depression shape is defined by V grooves or prisms having a pitch of 10 to 500 μm and a width of 1 to 250 μm.  
     
     
         3 . The light guide plate according to  claim 1 , which further comprises an antireflection layer on at least one of major planar surfaces.  
     
     
         4 . The light guide plate according to  claim 3 , which comprises an antireflection layer on a surface thereof that faces away from the surface having a fine projection-and-depression shape.  
     
     
         5 . The light guide plate according to  claim 3 , wherein: 
 the antireflection layer is of a multilayer structure comprising (1) at least one low-refractive-index layer and (2) at least one high-refractive-index layer comprising a metal oxide, a metal sulfide or a metal fluoride, wherein the high-refractive-index layer is located nearer to the light guide plate than the low-refractive-index layer.    
     
     
         6 . The light guide plate according to  claim 5 , wherein the low-refractive-index layer, and the high-refractive-index layer has a thickness of 5 to 500 nm.  
     
     
         7 . The light guide plate according to  claim 5 , wherein the metal oxide is selected from the group consisting of tantalum oxide, zirconium oxide, cerium oxide, niobium oxide, and a mixture thereof.  
     
     
         8 . The light guide plate according to  claim 5 , wherein an underlying layer of silicon oxide is interposed between a surface of the light guide plate and a metal oxide layer nearest to that surface.  
     
     
         9 . The light guide plate according to  claim 1 , wherein the alicyclic structure-containing polymer resin is either one of a hydrogenated product of a ring-opening polymer of a norbornene monomer or a vinyl alicyclic hydrocarbon polymer.  
     
     
         10 . A front-light type lighting unit for liquid crystal display systems, in which the light guide plate according to  claim 1  and a linear light source are built.  
     
     
         11 . A multilayer structure, which comprises a member obtained by molding or otherwise forming an alicyclic structure-containing polymer resin, a layer (A) containing SiOx (1≦x≦2) as a main component and provided thereon, and a layer (B) containing tantalum pentoxide as a main component and provided on the layer (A).  
     
     
         12 . The multilayer structure according to  claim 11 , wherein the layer (B) has a tantalum pentoxide content of 50% by weight or greater.  
     
     
         13 . The multilayer structure according to  claim 11 , wherein one or more inorganic compound layers and/or organic compound layers are formed on the layer (B).  
     
     
         14 . The multilayer structure according to  claim 11 , which provides a light guide plate for a front-light type lighting unit in a liquid crystal display system.  
     
     
         15 . An optical multilayer structure, wherein a member which is obtained by molding or otherwise forming an alicyclic structure-containing polymer resin and in which, upon held at 90° C. for 1 hour, an amount of gases generated therefrom is limited to 200 μg/m 2  or less, is provided on a surface thereof with a sputtering film having an average thickness of 50 to 1,000 nm with a thickness fluctuation of ±5% or less relative to the average thickness.  
     
     
         16 . The multilayer structure according to  claim 15 , wherein the sputtering film has a light ray transmittance of 50% or greater.  
     
     
         17 . The multi layer structure according to  claim 15 , wherein the sputtering film contains an oxide and/or a nitride as a main component.  
     
     
         18 . The multilayer structure according to  claim 15 , wherein the sputtering film is an antireflection film.  
     
     
         19 . The multilayer structure according to  claim 15 , which provides a front-light type light guide plate for a liquid crystal display device.  
     
     
         20 . A vapor deposition process, which comprises holding a composition for vapor deposition containing tantalum oxide as a main component in a molten state for 10 minutes or longer, solidifying the composition, and using the solidified composition to form a layer (A) containing tantalum oxide as a main component on an application member by vacuum vapor deposition.